Trenching excavator



Dec. l1, 192e. 1,609,293

C. L. GEORGE TRE'NCHING ExcAvAToR Filed March l, 1924 me/ufo@ y Patented ec. 7, 1926.

CHARLES L. Geenen, or rii\ini..fiir,v oiiio..

TRENCHENG EXCAVATOR.

Application filed March 1, 1924. Serial No. 696,254.

This invention relates to excavators of that type used primarily for digging trenches. in trenching machines utilizing a boom Vcarrying digger mechanism it has been the practice to depend upon the Weight of the boom and the mechanism carried thereby for maintaining the boom at the proper angle to insure digging to the desired depth. 1While this arrangement is effective While the machine is digging through light soil, the cables supporting the boom usually become slacked and the boom svvings upwardly if the soil is hard and sufficiently resistant to the action of the digging mechanism. Thus it has been ditiicult to dig uniform depth through-hard soil.

Tt is an object of the present invention to provide a simple and etcient means for holding the boom of the digging mechanism at any angle to which it may be adjusted thus insuring the production of'a trench of uniform depth irrespective of the nature of of the'soil through Which the cut is being made.

A further object is to provide a beam holding mechanism which can be applied readily to excavating machines already in use.

YWith the foregoing and other objects in view which Will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made Within the scope of what is claimed Without departing from the spirit of the invention..

In the accompanying drawings the pre- 1erred form of the invention has been shown.

In said draivings- I Figure l is a side elevation of a portion of a digging mechanism embodying the present improvements7 a portion of the body of the machine being indicated by broken lines.

Fig. 2 is a plan View of a portion of the boom and its holding mechanism, the segmental racls being shown in section.

Referring to the figures by characters of reference A designates generally the frame of a trench digging machine. A shaft l is supported thereby and pivotally mounted on this shaft is a boom 2 adapted to be adjusted angularly by a cable such as shown at B. An endless belt 3 is carried by the boom and has secured to it a series of digging buckets l of the usual or any preferred type.

A. transverse shaft 5 is carried by the boom and is provided, at each end, Wit-h a gear 6. These gears mesh with segmental racks .1 secured to the frame A at opposite sides of the boom, the said racks being concentric ivith the shaft "i, Thus it Will be seen that When the boom is svvung about its pivoted connection l the gears 6 and the shaft 5 will rotate.

Secured to the shaft 5 is a brake Wheel 8 anda brake band 9 is mounted in close proximity to the periphery of the Wheel.

One end of the Aband is iXedly mounted as shown at l0 while the other end thereof is secured to one end of a lever ll. This lever is fulcrumed between its ends, as shown at i2, and is adapted to be held againstmovement by a keeper 13 mounted on the boom.

Under normal conditions the band 9 is loose ony the Wheel 8 and boom 2 can thus be yadjusted readily to position at any desired angle relative to the `surface of the ground.

Vhen the boom has been brought Vto proper position so that the lower end of the digging mechanism is at thefdesired depth, theband 9 can be tightened on Wheel 8 by means of leverll. Thus rotation of the gearsf and shaft 5 will be prevented and the boom will therefore be retained at the angle to which it has been moved. This will result inthe digging of a trench of uniform depth through all kinds of soil because upward swinging of the boomwhen subjected to eX- cessive resistance'will be prevented. l

It is to be understood that the present in! vention 4can be combined with different kinds of digging machines utilizing swinging booms carrying digging mechanisms and obviously changes can 'be made to adapt the im.- provements tothe different machines.

vWhat is claimed is In a trenching machine the combination with a frame and a shaft "journaledthereon, of a boom mounted for angular adjustment about the shaft, means carried by the frame and connected to the boom for adjusting said boom angularly, arack secured to the frame loo and having downwardlyextended teeth, a

shaft j ournaled on the boom, a gear carried thereby and constantly in mesh With the rack, said rack constituting a shield for the gear, a brake Wheel rotatable with` the gear, and a brake hand extended about and cooperating With the Wheel for holding the gear against rota-tion, thereby to maintain the boom in any position to which it might he adjusted angularly.

In testimony .that I claim the foregoing 10 as my oWn, have hereto affixed my Signa ture. 'f

CHARLES L. GEoRGE. 

